1. Field of the Invention
The present invention relates to a screw feeding device for a power screw driving tool for driving in screws which are arranged in a strip-shaped screw magazine, with the device including a housing connectable with the power screw driving tool, a guide having a carrier projecting transverse to a setting direction of the screws for supporting the screw magazine, a support stepwise displaceable relative to the guide parallel to the setting direction and a bearing surface projecting, in the setting direction, beyond the guide, and an adjusting element for connecting the support with the guide.
2. Description of the Prior Art
German Publication DE-19522815.4 discloses a screw feeding device for a power screw driving tool for driving-in screws stored in strip-shaped screw magazine. The screw feeding device includes a housing, a guide, a support, an adjusting element, and a guide channel extending transverse to the setting direction of the screws. The housing can be connected with the power screw driving tool, and all of the components of the device listed above are displaceable relative to the tool in a direction opposite the setting direction against a biasing force. A carrier with a transporting channel for receiving and guiding the strip-shaped screw magazine projects from the guide in a direction transverse to the setting direction. The guide is surrounded by a support having a recess and a bearing surface that projects beyond the setting direction side of the guide. The guide is provided with three threaded bore extending in the setting direction in a spaced relationship to each other. In order to insure handling of screws having different length, the support can be stepwise displaced relative to the guide in a direction parallel to the setting direction. The support is secured to the guide with a screw that extends through the recess formed in the support and into one of the threaded bores of the guide.
The guide channel is limited, in the direction opposite to the setting direction by a setting direction end side of the guide. In the setting direction, the guide channel is limited by a counter surface of an intermediate member arranged in the support. The intermediate member can be secured, with a further screw, along the support in three different positions. The further screw extends into one of three side through-bores formed in the support and projects in a further threaded bore in the support.
In addition to the recess for receiving the screw attaching the support to the guide and to the through-bores for receiving the intermediate member-attaching screw, the support has side through-openings spaced from each other and the inner width of which is larger than the cross-section of the strip of the screw magazine on which separate, releasable screws are arranged.
The diameter of the recess formed in the support and the diameter of the screw, which secures the support to the guide, are so matched with each other that a small displacement of the support with respect to the guide is still possible when the securing or connecting screw is screwed in one of the threaded bores of the guide. This clearance is necessary for an axial retaining of the screw magazine strip on the screw feeding device during pressing of the power tool against a constructional component.
The formation of the circular recesses, the through-bores, and the through-opening in the support is connected with large expenses. In addition, an axial adjustment of the support with respect to the guide for accommodating different screw magazines having screws having a different length, can be effected only with the use of additional or separate working tools for screwing and unscrewing respective screws.
Accordingly, the object of the present invention is to provide a simple and economically manufacturable screw feeding device with a support that can be displaced relative to the guide between different displacement positions without using any additional working tool.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a support with a plurality of recesses arranged one after another in the setting direction, and an elastic support which cooperates, in its unstressed initial position, with at least one recess of the support and which enables, in its free prestressed disengagement position, a displacement of the support relative to the guide and to the adjusting element.
The adjusting element according to the present invention can be quickly and simply brought, by the tool user, without the use of any tools, in its prestressed disengaged position in which the support can be displaced relative to the guide. After the displacement of the support, the adjustment element is brought back into its position, in which it formlockingly cooperates with the support, by the prestressing force. The adjusting element can be economically produced of a plastic material by injection molding.
Advantageously, the adjusting element has at least one elastic arm pivotable in a plane extending transverse to the setting direction and transverse to the longitudinal extent of the guide channel and having a locking tongue formlockingly engageable with at least one stop of the guide for connecting the elastic adjusting element with the guide. The formlocking connection of the adjusting element with the guide facilitates mounting all of the components of the screw feeding device. E.g., both the adjusting element and the guide can be connected, in one operational step, with the housing of the screw feeding device and the connection sleeve of the power screw driving tool.
In order to achieve a good centering of the working tool with rotation receiving means provided in heads of screws, the strip of the strip-shaped screw magazine should be secured, during the driving-in process, with respect to the guide. This securing, e.g., can be achieved by clamping the strip in the guide channel. This, advantageously, is achieved by provided for a limited displacement of the adjusting element relative to the guide in a direction parallel to the setting direction. This limited displacement permits to change the height, which is measured in a direction parallel to the setting direction, of the guide channel that is formed by the adjusting element and the guide.
Advantageously, an elastic arm of the adjusting element has a connection web that engages the at least one recess in the support for axially securing the support on the guide. The connection web is proved in an end region of the elastic arm facing in a direction opposite the setting direction and connects a grip element with the elastic arm. The height of the connection web, which is measured in a direction parallel to the setting direction, corresponds to the inner length of the separate recesses measured in the same direction. The length of the connection web, which is measured in the direction parallel to the longitudinal extent of the guide channel, corresponds substantially to the width of the recesses measured in the same direction. Because the connection web forms part of an elastic arm, it can be easily displaced, without any tool and with a small force, out of a recess into a prestressed disengaged position in which the arm has been pivoted.
A particularly good formlocking connection of the adjusting element with the support is advantageously achieved when the adjusting element has two elastic arms projecting from a bottom of the adjusting element in the direction opposite the setting direction and pivotable toward each other in the same plane. Both elastic arms of the adjusting element and the recesses in the support are provided on a side remote from the magazine carrier that projects sidewise from the guide. The two arms can be easily brought in their disengaged position in which the connection webs do not project into the recesses of the support.
In order to prevent tilting of the adjusting element relative to the support when the support is displaced relative to the adjusting element, the adjusting element has two opposite, extending in a direction parallel to the setting direction, guide strips engaging in two opposite, likewise extending in a direction parallel to the setting direction, guide grooves formed in the support. Both guide strips are provided in the region of the bottom of the adjusting element so that they can still extend in the guide grooves when the two elastic arms are pivoted in their prestressed disengaged position.
In order to provide for an exactly parallel to the setting direction, guidance of the support relative to the power tool housing, the support has advantageously, on its outer side, two opposite, extending in the direction parallel to the setting direction, first guide regions that formlockingly cooperate with adjacent to each other guide edges provided on an inner side of the housing.
For a precise, parallel to the setting direction, guidance of the support relative to the guide, the support has on its inner side, two adjacent to each other, extending in a direction parallel to the setting direction, second guide regions which cooperate with extending in the direction parallel to the setting direction, guide surfaces provided on an outer side of the guide.
Preferably, each of the adjusting element and the guide has a guide web projecting into the guide channel. Both guide webs extend parallel to the longitudinal extent of the guide channel and lie in a plane that extends parallel to the setting direction. The two guide webs form side supports for the screw magazine strip in the guide channel.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to is construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.